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Thread: p01 2001 5.3 2 bar OS issues

  1. #1
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    p01 2001 5.3 2 bar OS issues

    Good evening all. I'm new to this computer thing with tuning and am pretty confused at this point. I'm following a checklist that tells me to kill the MAF, deceleration, COT, and EGR. I have a 1986 10 with a 5.3 from a 2001 Tahoe in it. I welded my own exhaust and put a 72mm turbo on it and I upgraded to larger injectors. Ford part number M-9593-g302. They are 47 lb/hr injectors. I also have a 2.5 BAR MAP sensor part number 12614973 from a Cobalt. Everything else is stock. I do have a wideband sensor, independent of the scanner, wired up and working correctly. I have what seems like a myriad of issues but I will ask what I think is the root issue. When I switched to the 2BAR OS I followed the steps on switching the VE table information and updating injector data as well MAP calibration. I went to start and it would either dump fuel and choke or it wouldn't start at all. I tried giving it more airflow through the idle tables. That didn't work. I finally got it to idle somewhat decently, but still rich and it hunts really bad, by reducing the VE table by half. What I thought was also weird is that it is reading somewhere between 13.5 to 15 on the wideband. So the fueling is somewhat close. I am new to tuning with computers but it doesn't feel right having to half the VE table. Thank you for your time and any help is greatly appreciated.

  2. #2
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    This is the file that had it running decently well. I also attached the stock version to compare against.
    Attached Files Attached Files

  3. #3
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    You're missing half your injector data. You still need the offset vs volts data and the short pulse adder data for those injectors. Just changing the flow rate and min injector pulse width is not enough. I have no idea if you can even find that data for them because I've never used them. I'd honestly just find some newer GM flex fuel injector that are 50 or 52lb/hr from a 6.0 or 6.2 truck as those will have all the data you need. Just need a spreadsheet that converts the GEN 4 data into GEN 3 style.

    That MAP data looks wrong too for a 2 bar MAP sensor. The key on engine off KPA reading will be roughly 100kpa at sea level. The data log is pegged at 105kpa because the 2 bar MAP channel isn't being logged, so the actual number is much higher. I think the settings for that map at like 208/10 or 210/10 or 8 but I forget off hand.

    Fix those things and it should run a lot better. Obviously you'll need to return to a stock like VE table with maybe a little bit of fuel removed but not 50%.
    2016 Silverado CCSB 5.3/6L80e, not as slow but still heavy.

    If you don't post your tune and logs when you have questions you aren't helping yourself.

  4. #4
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    2 bar os issues

    Thanks so much for the reply. I thought that as well because I am in Oceanside, CA. So I am at sea level. I used 200 and 10.33 and it would read the same thing. 105kpa. Once, I deleted the Manifold Absolute Pressure (SAE) PID and added the Manifold Absolute pressure 2 BAR pid and it would read 0. If I had both on the scanner at the same time the reading would flash in between 0 and 105. Thats probably normal. But some other stuff happens too, what about sometimes it doesn't start reading anything for a few minutes. I revved up to 2500 on the scan i posted and i hear the turbo blow off, very lightly because I have the valves backed off so it runs a little more normally, and the kpa continues to read off. I know you're right about injector data and MAP being off but have you heard of bad OS's or faulty computers causing this? I mean it is from a 2001 Tahoe. It just seems off becuase no matter what I did to the fan setting I couldn't get those to work either. It feels like the computer doesn't or barely responds to changes I make. This data is obviously off for most things needed to start tuning but the MAP calibration is close to what you were saying and check out the scan. Its still pegged at 105 like you were saying and when it starts the kpa flutters to 103 once or twice and then stays at 105. This is why I'm posting and asking for help. I am at a complete loss.
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  5. #5
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    I meant the pressure at 2500 rpm still reads like 80kpa when i was talking about the turbo.

  6. #6
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    You have to have a load on the engine for it to make boost if thats what you meant.

    Looks like its running what the table is commanding while coolant temp is low (95*) when the MAP reading is 105kpa.
    [ECM] 12430 - Open Loop F/A vs. Coolant Temp vs. MAP
    Last edited by RDF1; 12-20-2021 at 10:21 PM.

  7. #7
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    Damn, I feel retarded. My bad, this is my first turbo build. I did a pretty decent stroker build (carburetor) so i wanted to try computer tuning. Please bear with me guys. I'll still look into the injectors 5FDP. Thanks everyone and please tell me if anything else looks off.